Abstract

Objectives: A variety of mechanical processes can result in ante-mortem dental chipping. In this study, chipping data in the teeth of Homo naledi are compared with those of other pertinent dental samples to give insight into their etiology. Materials and Methods: Permanent teeth with complete crowns evidencing occlusal wear were examined macroscopically. The location, number, and severity of fractures were recorded and compared to those found in samples of two other South African fossil hominin species, as well as in samples of non-human primates (n= 3) and recent humans (n= 7). Results: With 44% of teeth affected, Homo naledi exhibits far higher rates of chipping than the other fossil hominin samples. Specifically, 50% of posterior teeth and 31% of anterior teeth display at least one chip. The maxillary teeth are more affected than the mandibular teeth (45% vs. 43%, respectively), 73% of molar chipping occurs on interproximal surfaces, and right teeth are more often affected than left teeth (50% vs. 38%). Discussion: Results indicate that the teeth of H. naledi were exposed to acute trauma on a regular basis. Because interproximal areas are more affected than buccal, and posterior teeth more than anterior, it is unlikely that non-masticatory cultural behavior was the cause. A diet containing hard and resistant food, or contaminants such as grit, is more likely. The small chip size, as well as steep occlusal wear and cupped dentine on some molars is supportive of the latter possibility. This pattern of chipping suggests H. naledi differed considerably – in terms of diet, environment, and/or specialized masticatory processing— relative to other African fossil hominins.

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Article

Additional Information:

This is the accepted version of the following article: Towle I, Irish JD, De Groote I. Behavioral inferences from the high levels of dental chipping in Homo naledi. Am J Phys Anthropol. 2017;164:184–192, which has been published in final form at https://doi.org/10.1002/ajpa.23250